Many things including protests
Jet stream and cold front of course
Instead of the troika coming, there was a power struggle and Stalin took control of the country. He managed to remove all his political opponents and collectivize the properties which led to a rapid industrialization. There was no troika because Stalin ruled himself with an iron fist. He stayed in that position until he died in 1953.
Answer:
That would be the Mackenzie river because it is the largest beeing over 4000 kilometers long
Explanation: